A multicast service in an access device is an important and widely used service, and a PON (Passive Optical Network, passive optical network) system belongs to a broadcasting system, so it is more advantageous to perform the multicast service over the PON.
There are two method for forwarding an OLT (Optical Line Terminal, optical line terminal) multicast program in the prior art; one is a mode of forwarding according to PON replication, while the other one is a mode of forwarding according to user replication. However, according to the solutions of the prior art, the OLT may forward the multicast program only in the mode of forwarding according to PON replication, or forward the multicast program only in the mode of forwarding according to user replication, so it is unable to support the two forwarding modes according to the actual needs of the user at the same time.